Ensure the .NET SDK sets `sentry.origin` for Structured Logs according to the documentation

[alexsohn1126]

Description

Refer to getsentry/sentry-docs#15127 for discussions on why this change was made.

tldr: We will consolidate sentry.origin for Logs according to the new specs:

• https://develop.sentry.dev/sdk/telemetry/logs/#sdk-integration-attributes

From the updated docs:

Logs can be generated in three ways:

• User calls Sentry’s Logging API directly: SDKs MUST NOT send a sentry.origin. As logs are charged based on size, we want to minimize the size of logs, and we intentionally deviate from the original Trace Origin documentation.

• Captured from a logging library: Use auto.log. format. where is the relevant integration. For example, the .NET Serilog library emits:

{ "sentry.origin": "auto.log.serilog" }

• Auto-emitted logs from other instrumented systems: Use the auto.. format as outlined in Trace Origin documentation.

{ "sentry.origin": "auto.db.prisma" }

[linear]

NET-490